Apparatus and methods for delivering coiled prostheses

Abstract

Methods and apparatus for delivering prostheses to body lumens, such as stents and grafts to blood vessels, utilize a delivery device which carries one or more linearized elements. The linearized elements assume non-linear configurations, particularly helical configurations, when advanced and released from the delivery device. By selectively controlling the length and/or number of elements delivered from the delivery device, extended and disseminated disease within the body lumens may be effectively treated.

What is claimed is: 
     
       1. A method for delivering a prosthesis to a stenotic region of a blood vessel, said method comprising:
 introducing a delivery device to an interior of the blood vessel, wherein said device carries a plurality of discrete helical element, each of the plurality of discrete helical elements having a predetermined length and being separable from the remainder of helical elements; 
 advancing a first number of the discrete helical elements relative to the delivery device within the interior of the blood vessel, wherein advancing comprises drawing and rotating the delivery device relative to the body lumen while pushing the first number of discrete helical elements from the delivery device and wherein the first number of the discrete helical elements assume a helical configuration which traverses a surface region of the interior of the blood vessel as the first number is advanced; 
 viewing the length of the first number relative to the length of the stenotic region; 
 selecting a first number of a discrete helical elements so that the combined length of the first number of discrete helical elements with a separate element coupled to the catheter matches the length of the stenotic region of the blood vessel, the first number being operator selectable between 1 and at least 2; 
 separating the first number of discrete helical elements from a second number of discrete helical elements; 
 releasing the first number of the one or more discrete helical elements in the non-linear configuration from the delivery device into the stenotic region of the blood vessel, wherein upon release the first number forms and remains a generally tubular scaffold to inhibit closure of the stenotic region without substantially inhibiting blood flow through the blood vessel; and 
 maintaining the second number of the discrete helical elements in the delivery device after the first number is released; 
 wherein the first number of discrete helical elements assumes a helical configuration and the delivery device is rotated as the first number of discrete helical elements are pushed. 
 
     
     
       2. A method for delivering a prosthesis to a stenotic region of a blood vessel, the method comprising:
 introducing an elongate catheter shaft having a proximal end, a distal end and a lumen therebetween into the blood vessel, the shaft carrying a self-expandable prosthetic element disposed in the lumen in a linearized configuration while constrained in the lumen and adapted to radially expand into a helical configuration upon deployment, and wherein the prosthetic element is separable into a first prosthesis having a first length and second prostheses having a second length prior to release from the catheter shaft; 
 advancing the first length of the prosthetic element from the lumen while the second length is retained in the lumen in the linearized configuration; and 
 separating the first prosthesis from the second prosthesis with a separating element coupled to the catheter shaft such that the first prosthesis resiliently expands to the helical configuration outside the lumen while the second prosthesis is retained in the catheter shaft in the linearized configuration, the helical configuration being generally tubular with an open longitudinal passage therein adapted to provide a scaffold to inhibit closure of the blood vessel without substantially inhibiting blood flow through the longitudinal passage, wherein the first prosthesis continuously engages a wall of the blood vessel along substantially all of the first length. 
 
     
     
       3. A method according to  claim 2 , wherein separating comprises severing the first prosthesis from the second prosthesis after the first prosthesis has traversed the stenotic region. 
     
     
       4. A method according to  claim 2 , further comprising viewing the first prosthesis relative to the length of the stenotic region. 
     
     
       5. A method according to  claim 2 , wherein advancing comprises drawing the catheter shaft relative to the blood vessel and pushing the first prosthesis from the lumen as the catheter shaft is drawn. 
     
     
       6. A method according to  claim 5 , wherein the rate of drawing the catheter shaft is varied relative to the rate of pushing the first prosthesis from the catheter shaft catheter in order to control the pattern in which the first prosthesis is laid on the stenotic region. 
     
     
       7. A method according to  claim 5 , wherein the rate of drawing the delivery catheter is varied relative to the rate of pushing the first prosthesis from the delivery catheter in order to control the pitch of the first prosthesis. 
     
     
       8. A method according to  claim 5 , further comprising rotating the catheter shaft as the first prosthesis is pushed. 
     
     
       9. A method according to  claim 2 , wherein the prosthetic element is at least partially malleable and wherein advancing comprises deforming the first prosthesis into the helical configuration as the first prosthesis is advanced. 
     
     
       10. A method according to  2 , wherein the prosthetic element is pre-shaped with a spring memory and wherein advancing comprising releasing the first prosthesis from a linearized constraint. 
     
     
       11. A method according to  claim 10 , wherein the constraint is the lumen and wherein advancing comprises pushing the first prosthesis from the lumen as the catheter shaft is drawn relative to the body lumen. 
     
     
       12. A method according to  claim 11 , wherein the rate of drawing the catheter shaft is varied relative to the rate of pushing the first prosthesis in order to control the pattern in which the first prosthesis is laid on the stenotic region. 
     
     
       13. A method according to  claim 12 , wherein the first prosthesis is advanced so that it traverses the stenotic region with diffuse disease over a length of at least 10 mm. 
     
     
       14. A method according to  claim 12 , wherein the element is coated or loaded with an active substance which inhibits hyperplasia after the first prosthesis has been placed in the blood vessel. 
     
     
       15. A method according to  claim 2 , wherein the prosthetic element is composed at least partly of a bioabsorbable material. 
     
     
       16. A method according to  claim 15 , Wherein the prosthetic element comprises a metal scaffold covered with a polymeric layer. 
     
     
       17. A method according to  claim 2 , wherein the first length is different than the second length.